Calas later rebelled against his wealthy family background by becoming a Trotskyist, strongly influenced in his turn to radical politics by witnessing the human tragedy of the refugees of the 1922 Asia Minor catastrophe flooding the streets of Athens.
Calas's poetry, published under the pseudonym Nikitas Randos, went through several stylistic changes which reflected his artistic curiosity and interest in the modernist trends of the early 20th century, such as futurism, expressionism and surrealism.
In 1938, Calas published a book of Freudo–Surrealist–Trotskyist criticism in French, Foyers d’incendie (Hearths of Arson) which revealed his influence by theoreticians of the Frankfurt School, especially Wilhelm Reich, as well as the manifesto "Towards a Free Revolutionary Art" formulated by Leon Trotsky, Diego Rivera and André Breton in Mexico in 1938.
He was finally able to leave Europe behind in the beginning of 1940 after receiving a visa through the help of his friend Sherry Mangan, an American Trotskyist poet and journalist working for Time magazine.
During this time Calas became a research-associate and consultant for the renowned anthropologist Margaret Mead and in 1953 their collaboration resulted in the publication of an anthropological anthology entitled Primitive Heritage.
Calas received three successive grants from the Bollingen Foundation (1949–1951) to write a study of the triptych The Garden of Earthly Delights by Hieronymus Bosch but failed to get it published and continued rewriting the manuscript until his death.
After spending some time in Greece during the 1950s, sorting out the family affairs after the death of his father, Calas began to write poems again in Greek in a cryptic and satirical style.